1. It’s not Old Irish.
2. It’s not Old Irish.
3. It’s not Old Irish.
101. Did we mention it’s not Old Irish?
To feel better about any language currently giving you grief, even nasty things like Greek or Latin, read this account of Old Irish verbs and their tricksy ways at The Expvlsion of the Blatant Beast.
Hat-tip to GoblinPaladin for the link.